Well as far as I remember, the Airbus FMGC is clever enough to comply with altitude restrictions as entered, despite having a different setting on the altimeter. Don't know about Boeings, although I should!
The STAR at YBBN is an example of poor ATM, whether by design or subsequent modification of the procedure. I think it is unacceptable in today's busy environment to 'design in' potential traps for unwary pilots and controllers.
The low transition altitudes in the U.K. are another example, especially if the SID clears you to a Flight Level.
Procedures and airspace design should be as simple as possible and subject to several 'test flights' in the simulator before being released. Perhaps they already are but sometimes one is left wondering, 'who on earth came up with this idea?'
The proposed raising of the Trans Alt in the U.K. to 18,000ft is a welcome move. Let's hope that the rest of the world follows suite. That will still leave the CIS, Mongolia and China (and N Korea) to get with the programme and ditch Meters and QFE (and mmHg)!